Field of the Invention
The invention relates to frequency modulation discriminators, and more particularly to frequency modulation discriminators using digital signal processing techniques.
Frequency modulation (FM) is a commonly used technique for imposing an information-carrying signal onto a carrier signal for transmission to a remote location. When the signal is received at the remote location, it is necessary to extract, or demodulate, the original information signal from the carrier signal using a frequency discriminator.
A common technique form of discriminator uses the quadrature components of the modulated signal to derive the original information signal. Examples of this are found in U.S. Pat. Nos. 3,500,217 to Allen, 4,583,048 to Gumacos et al., and 3,568,067 to Wiliford.
In the past as the aforementioned patents indicate, it was common to perform the demodulation using entirely analog techniques. In recent years, however, the rise in the use of computers and digital electronics has led to the desire to perform demodulation using digital signal processing techniques.
The primary object of the present invention is to provide an FM demodulator which will operate efficiently on digitally-sampled signals.
Other objects of the invention are to provide an FM demodulator which does not need to be adjusted and which provides a high level of computational precision.